Composition for encapsulating signal transmission devices

ABSTRACT

A signal transmission device comprising an encapsulated segment produced by a method which comprises contacting the segment of the signal transmission device with an effective amount of a room-temperature curable composition comprising: (1) a hydroxy-functional compound having a molecular weight of greater than 500 and a hydroxy functionality of 2 or more; (2) an epoxy-functional compound having an epoxy functionality of 2 or more; and (3) a curative catalyst, in an amount effective to crosslink the epoxy and hydroxy components of the respective epoxy-functional and hydroxy-functional compounds.

This is a divsional of U.S. patent application Ser. No. 08/907,576,filed on Aug. 8, 1997, now U.S. Pat. No. 5,940,570, which is adivisional of U.S. patent application Ser. No. 08/655,495, filed on May.30, 1996, now U.S. Patent No. 5,698,631.

TECHNICAL FIELD

This invention relates to a composition useful for encapsulating signaltransmission devices. More particularly, this invention relates to acomposition comprising a multi-functional epoxy component, amulti-functional hydroxy component, and a curative catalyst.

BACKGROUND OF THE INVENTION

Telecommunication cable is frequently employed in situations where wateris able to enter and migrate thoughout the cable system. Water entryinto either metallic and fiber-optic cables is undesirable because suchentry leads to corrosion and deterioration of desired transmissionproperties, particularly at the sites where the cables are splicedtogether.

To protect such cable systems, it has become common practice to encasecertain cable segments by a closure that functions as an extension ofthe cable sheath or cover.

In addition, it has become common practice to encapsulate such cablesegments with a curable encapsulant, in order to prevent watermigration. Examples of cable segments typically placed in closures andso encapsulated include areas where two or more cables are splicedtogether, at the ends of cable, junctions between air-pressurized cableand grease-filled cable, and pressure blocks.

It is often necessary for the encapsulant to be re-enterable for repairor other modification. For an enclosure to be re-enterable, theencapsulant must be capable of being entirely removed from around thesplice area in a simple manner (such as by hand), because it is notdesirable to use tools or other implements near copper wire, opticfilament, or delicate parts. In this way, wire and filament connectionsare not damaged, and copper wire insulation as well as fiber-opticcoatings are not disturbed.

Because the splice closures for telecommunication devices are typicallyencapsulated at field locations where cable is layed, the encapsalantsare applied by a variety of individuals under a variety of conditions.It is desirable, therefore, to have a clear, easy to mix, two-partsystem where adequate mixing can be readily determined from the colorchange of the system. Sufficient mixing is necessary to obtain highquality splices. Clarity of the encapsalant aids in observation of boththe filling process and eventual re-entry process.

Encapsulants of this type are often required to provide acceptableadhesion to grease, because electrical and telephone cables typicallycontain a number of individual conductors that are often covered withgrease as protection from water penetration. U.S. Pat. No. 4,176,240describes a grease composition which is typical of the types used aswater-proofing agents in electrical and telephone cables.

Urethanes which are made by reacting a polyol with an isocyanate, suchas those described in U.S. Pat. Nos. 4,375,521; 4,596,743; and4,666,968, have been described as useful for encapsulation oftelecommunication equipment and devices include urethanes.

Urethanes have numerous drawbacks. Urethanes are inherently tough,resilient materials, which renders them inherently difficult tore-enter. Compatability with hydrocarbon-based greases is also poor forurethanes, as is adhesion to grease-coated conductor wires.

In an alternative method of curing polyols, hydroxy-containing compoundsare reacted stoichiometrically with maleic anhydride-modifiedpolybutadiene to form thermosetting ester compounds. Organic amines,phosphines and/or organometallic soaps are used to catalyze theseesterification reactions. For example, U.S. Pat. Nos. 4,857,563;4,985,475; and 5,169,716, describe encapsulant compositions which areextended reaction products of an admixture of ananhydride-functionalized composition and a crosslinking agent. Suchencapsulants are, however, very difficult to re-enter and adhere poorlyto grease-coated wires. The ester linkages formed in these encapsulantsare also susceptible to hydrolytic cleavage.

U.S. Pat. No. 5,140,075 describes an encapsulation compositionconsisting of a low molecular weight epoxy-grafted polymer and acurative. This composition results in a material that is opague, makingobservation of filling and re-entry more difficult.

It is an object of the present invention to provide a room-temperaturecurable composition which can be used as a durable encapsulant forsignal transmission devices, wherein the encapsulant is easilyre-enterable, possesses a high degree of transparency and clarity, iscapable of protecting the signal transmission devices from water andother external damage, and has excellent adhesion to grease-coatedconductor wires.

SUMMARY OF THE INVENTION

This invention relates to a room temperature curable compositioncomprising: (1) an epoxy-functional compound having an epoxyfunctionality of two or more; (2) a hydroxy-functional compound having amolecular weight of greater than 500 and a hydroxy functionality of twoor more; and (3) a curative catalyst, in an amount effective tocrosslink the epoxy and hydroxy components of the epoxy-functional andhydroxy-functional compounds.

This invention relates to a method for encapsulating a signaltransmission device using such a composition.

This invention additionally relates to an encapsulated signaltransmission device prepared by such a method.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of this invention, the term "epoxy-functional compound"means a chemical compound comprising at least one three membered etherring (epoxy group) of the structure ##STR1## The term "multi-functionalepoxy compound" means an epoxy-functional compound comprising an averageof two or more epoxy groups per molecule. The multi-functional epoxycompound is present in the instant composition in an amount of about 5%(w/w) to about 98% (w/w), preferably, 10% (w/w) to about 60% (w/w), and,more preferably, 30% (w/w) to about 50% (w/w), of the total mixture ofthe multi-functional epoxy compound and the multi-functional hydroxycompound (excluding diluents). Useful multi-functional epoxy compoundsinclude epoxidized olefinically unsaturated natural oils, epoxidizedunsaturated esters, aromatic glycidyl ethers, aliphatic glycidyl ethers,epoxidized olefinically unsaturated polymers, and glycidyl etherfunctional polymers, and the like, as well as combinations thereof.

A preferred multi-functional epoxy compound useful in the composition ofthis invention, is an epoxidized soybean oil (such as Flexol EPO,available from Union Carbide).

For the purposes of this invention, the term "hydroxy-functionalcompound" means a chemical compound comprising at least one functionalgroup (hydroxy group) of the structure ##STR2## The term"multi-functional hydroxy compound" means a hydroxy-functional compoundcomprising an average of two or more hydroxy groups per molecule. Themulti-functional hydroxy compound is present in the instant compositionin an amount of about 2% (w/w) to about 95% (w/w), preferably, about 40%(w/w) to about 90% (w/w), and, more preferably, 50% (w/w) to about 70%(w/w), of the total mixture of the multi-functional epoxy compound andmulti-functional hydroxy compound (excluding diluents).

Suitable multi-functional hydroxy compounds include hydroxy-terminatedpolybutadiene (e.g., Poly bd R45HT, Elf Atochem, Philadelphia, PA),hydroxy-terminated poly-butadienestyrene, hydroxy-terminatedpolybutadiene-acrylonitrile, hydroxy-functionalized ethylene-propylenecopolymers and terpolymers, hydroxy-functionalized polyisoprene, castoroils (e.g., Caschem DB oil, Caschem, Bayonne, N.J.), as well ascommercially-available polyether polyols, polyester polyols, and thelike, and combinations thereof.

For the purposes of this invention, the term "curative catalyst" means achemical compound or mixture of chemical compounds which will cause themixture of the multi-functional epoxy compound and multi-functionalhydroxy compound, to form a cross-linked network.

The amount of curative catalyst which can be employed will vary inaccordance with a number of factors including the particular curativecatalyst that is selected, the degree of epoxidation present on thegraft polymers, desired gel time, the degree of cure desired, and soforth. In general, the amount of curative catalyst will vary from about0.5 parts to about 100 parts, preferably, about 2 to about 50 parts, andmost preferably, about 10 to about 30 parts, per 100 parts of the totalmixture of the multi-functional epoxy compound and the multi-functionalhydroxy compound.

Suitable curative catalysts include acidic catalysts such as thosecomprising a Lewis acid. For the purposes of this invention, the term"Lewis acid" means compounds having vacant orbitals in the outer shellof at least one of its atoms, thereby being reactive with compoundshaving a high electron density. Suitable Lewis acids include, e.g.,boron trifluoride, tin tetrachloride, aluminum trichloride, aluminumtribromide, zinc chloride, silicon tetrachloride, and ferric chloride,and the like.

A preferred curative catalyst is a catalyst composition comprising: (1)a catalytically effective amount of a Lewis acid, and (2) a titanatehaving the structure

    Ti(OR.sup.1)(OR.sup.2)(OR.sup.3)(OR.sup.4)

wherein R¹, R², R³ and R⁴ are each independently alkyl or aryl.

Suitable titanates include tetraisopropyl titanate, tetra-n-butyltitanate, tetraisobutyl titanate, tetra-t-butyl titanate,tetra-2-ethylhexyl titanate, tetra-dodecylphenoxy titanate,tetranonylphenoxy titanate, and diisopropyl dinonylphenoxy titanate, andthe like.

Both the molar ratio of titanate to Lewis acid as well as the Lewis acidconcentration in the catalyst composition can vary. However, it isgenerally preferred that the molar ratio of titanate to Lewis acid be inthe range of about 0.5-20, more preferably about 0.5-10, and mostpreferably about 1-6. Also, the Lewis acid concentration in the catalystwill generally be about 0.005-0.1 moles per 100 grams of catalystcomposition, more preferably about 0.0075-0.05 moles per 100 grams ofcatalyst composition, and most preferably, about 0.01-0.03 moles per 100grams of catalyst composition.

Such catalyst compositions can additionally contain certain additives aswell as certain diluents, well known to a person having ordinary skillin the art. Suitable additives include esters based on natural-productoils as well as esters based on hydrocarbon oils. Suitable diluents,which can either be reactive or nonreactive, include dioctyl azelate andoctyl tallate, in an amount that is effective for increasingpourability.

The composition of this invention can further include cure accelerators,in order to decrease their gelling or setting time. Any of thecommercially-known epoxy-cure accelerators may be employed, providedthat they are compatible with the end product and its intended use.Preferred accelerators include alkylphenols such as nonylphenol,dodecylphenol, and the like.

Preferred amounts of accelerator utilized will depend upon a variety offactors, including the particular catalyst which is selected, the amountof epoxy-functionality that is present, the amount and type of curativethat is employed, and so forth.

For the purposes of this invention, the term "signal transmissiondevice" means a device for transmitting a pulsed or modulated signalfrom one location to another. Examples of signal transmission deviceswhich can be encapsulated by the compositions of this invention includecopper telecommunications cable, fiber optic telecommunications cable,and CATV cable.

Because of its ability to cure at room temperature, the compositions ofthis invention are well-suited for such on-site encapsulation of cablesegments as splices, pressure blocks, and end blocks.

One method for encapsulating a telecommunication cable segment using thecomposition of this invention is described below. The telecommunicationcable segment can be of the metallic type or the fiber-optic type. Thetelecommunication cable segment is placed within a closure. Such aclosure serves to act (at least in part) as a retainer for thecomposition of this invention. The closure can generally be of anyuseful configuration or composed of any useful material.

The composition of this invention is typically then prepared bycombining a mixture of the multi-functional epoxy compound and themulti-functional hydroxy compound, with the curative catalyst. Theresultant composition can be suitably mixed by any means effective todisperse adequately the curative catalyst within the mixture, in amanner such that curing will occur.

This composition is then poured into the closure such that thecomposition covers at least that portion of the cable segment to beprotected.

Such pouring can be accomplished at any temperature which is below thedecomposition temperature of the composition and which will not causedamage to the cable segment to be protected, preferably at roomtemperature or at moderately-elevated temperatures.

The composition of this invention can be easily adapted for on-siterepairs due to the ease of application. Moreover, the composition ofthis invention exhibits excellent adhesion to wire.

The improved compatibility of the compositions of this invention withcable filler as well as improved conductor wire-adhesion properties ofthe compositions of this invention can prevent or greatly reduce thefrequency of water corrosion related failures.

Should future re-entry be necessary, the advantageous re-entrycharacteristics of the encapsulant produced from the composition of thisinvention, allows changes to be made with minimum risk of damage toother conductors.

The following examples are presented to illustrate the presentinvention.

EXAMPLE 1 Preparation of Lewis Acid Catalysts Regulated With AlkylTitanates

Eight hundred and seventy-eight grams (878 g) of octyl tallate(commercially-available from CP Hall of Akron, Ohio., as Plasthall 100,a diluent used to adjust catalyst viscosity) was weighed into aone-gallon Pyrex jar. 1,357 g of dodecyl phenol was then added into thejar, with stirring, to form a light yellow solution. 585 g oftetraethylhexyl titanate was subsequently slowly added to the lightyellow solution in the jar, with stirring.

Addition of the titanate liberated heat and produced a dark redsolution, indicative of the formation of tetradodecyl phenolatotitanate.

Finally, 180 g of anhydrous tin tetrachloride was added to the dark redsolution in the jar, with the liberation of heat, and the resultantmixture was rolled overnight on a roller mill to ensure uniformity ofthe mixture, to produce Sn/Ti Catalyst 1A.

A second catalyst (Sn/Ti Catalyst 1B) was prepared in a similar manneras Sn/Ti Catalyst 1A, using 828 g Plasthall 100, 749 g dodecyl phenol,323 g tetraethylhexyltitanate, and 99.5 g tin tetrachloride.

EXAMPLE 2 AND COMPARATIVE EXAMPLES A-C Preparation of EncapsulantCompositions

To prepare the composition of Example 2, 100 g of Polybutadiene R45HT(Elf Atochem NA), a hydroxy-functionalized polybutadiene liquidelastomer having 2.3 hydroxy groups per chain and a molecular weight of2800, was weighed into a beaker. 20 g of Paraplex G-60 Epoxy (CP Hall),an epoxidized soybean oil having 4.4 epoxy groups per chain and amolecular weight of 1000, was then added to the Polybutadiene R45HT inthe beaker. Finally, 20 g of the Sn/Ti Catalyst 1A prepared in Example 1above, was added to the mixture of Polybutadiene R45HT and Paraplex G-60Epoxy in the beaker, to produce the composition of Example 2. Additionof the catalyst was carried out with stirring but with no added heat,because the reaction was exothermic.

The composition of Comparative Example A was prepared as described abovefor the composition of Example 2 except that no catalyst was used. Thecomposition of Comparative Example B was prepared as described above forthe composition of Example 2 except that no Paraplex G-60 Epoxy wasused. The composition of Comparative Example C was prepared as describedabove for the composition of Example 2 except that no PolybutadieneR45HT was used.

A wooden stick was then dipped (frequently) into each composition untilthe composition exhibited a tendency to snap back. The time from mixingto snap-back condition was considered the gel time. The recipes for thecompositions of Example 2 and Comparative Examples A, B and C, as wellas the physical properties of each cured composition, are listed belowin Table I.

In Table I and the other tables presented below, the followingprocedures were used for physical tests and sample preparation.

Procedures For Physical Testing And Sample Preparation

To prepare a sample, 35 grams of the composition to be tested was pouredinto an aluminum cup, 76 millimeters (3 inches) in diameter by 15.9millimeters (5/8 inches) deep, which had previously been sprayed with acommercially available mold-release product. Depending upon thecomposition being tested, the sample was then cured either at roomtemperature in a dessicator or at elevated temperature in acirculating-air oven. Final cured sample thickness was 9.5 millimeters(3/8 inches).

Regarding our determination of cure properties, the cure state thusdetermined was a qualitative assessment. The durometer value of thecured sample was measured using a Shore 00 type durometer, which wasattached to a mounting rod. An 800 gram weight was placed on top of thedurometer mounting rod. Measurements were taken 15 seconds after thedurometer's probe was placed on the sample surface.

To determine sample elongation, a 12.7 millimeter (1/2 inch) wide stripwas cut from the center of the cured material and a 12.7 millimeter (1/2inch) gage mark placed in the center of the strip. The strip was thenput into a jig and extended at a rate of 254 millimeters (10 inches) perminute. A ruler was held along the side of the sample during extensionto determine the elongation at break.

                  TABLE I                                                         ______________________________________                                        Example   A         B         C       2                                       ______________________________________                                        Polybutadiene                                                                           100       100       --      100                                     R45HT                                                                         Paraplex G-60                                                                           20        --        20      20                                      Epoxy                                                                         Sn/Ti Catalyst 1A                                                                       --        20        20      20                                      Gel Time @ RT                                                                           >5 hr.    >5 hr.    10 sec. 11 min.                                 Cured Properties                                                              Cured State                                                                             No Cure   No Cure   Crumbled                                                                              Flexible                                00 Durometer                                                                            --        --        N/T     36                                      Elongation at                                                                           --        --        <25%    50-75%                                  Break                                                                         ______________________________________                                    

Example 2 together with Comparative Examples A and B demonstrate that amulti-functional epoxy compound, a multi-functional hydroxy, and acurative catalyst are needed to produce an acceptable cured product.

EXAMPLES 3-5 AND COMPARATIVE EXAMPLES D-I

Following the procedure described in Example 2 and Comparative ExamplesA-C above, the compositions of Examples 3-5 and Comparative Examples D-Iwere prepared, cured and evaluated using the multi-functional hydroxycompounds listed in Table II below.

                  TABLE II                                                        ______________________________________                                        Comparative Examples D, E and F                                                                 Polypropylene Glycol (PPG)                                                    Molecular Weight 425                                        Comparative Examples G and H                                                                    PPG Molecular Weight 1000                                   and Example 3                                                                 Comparative Example I and                                                                       PPG Molecular Weight 2000                                   Example 4                                                                     Example 5         Polytetramethylene Ether Glycol,                                              MW 1000 (PTMEG-1000)                                        ______________________________________                                    

The multi-functional epoxy compound used in Examples 3-5 and ComparativeExamples D-I was Paraplex G-60 Epoxy and the curative catalyst was Sn/TiCatalyst 1A.

Tables III and IV below describe gel time, summarize the properties ofthe multi-functional hydroxy compounds, and display the cured propertiesof the compositions.

Data in Tables III and IV demonstrate that the polyol-substitutedmulti-functional hydroxy compounds (hereinafter "polyols") having amolecular weight greater than 500 produce useful compositions.

Polyols most preferred have a molecular weight that ranges from1000-4000. These experiments also tend to show that the amount ofmulti-functional epoxide needed to cure the polyol is dependent upon thepolyol molecular weight. That is, lower molecular weight polyols requiremore epoxide. Required epoxide ranges from 5-50% of the polyol-epoxidemixture. A range of 10-50% of the polyol-epoxide mixture is preferred,and 17-50% of the polyol-epoxide mixture is most preferred.

                                      TABLE III                                   __________________________________________________________________________    Comp. Example                                                                          D    E    F    G    H   I                                            __________________________________________________________________________    PPG-425  83   70   50   --   --  --                                           PPG-1000 --   --   --   83   70  --                                           PPG-2000 --   --   --   --   --  83                                           PTMEG-2000                                                                             --   --   --   --   --  --                                           Paraplex G-60                                                                          17   30   50   17   30  17                                           Sn/Ti Catalyst 1A                                                                      17   17   17   17   17  17                                           Polyol Properties                                                             Type     Ether                                                                              Ether                                                                              Ether                                                                              Ether                                                                              Ether                                                                             Ether                                        Functionality                                                                          2    2    2    2    2   2                                            MW       425  425  425  1000 1000                                                                              2000                                         Gel Time @ RT                                                                          >3 hr.                                                                             >20 hr.                                                                            >20 hr.                                                                            >3 hr.                                                                             >20 hr.                                                                           3 hr.                                        Cured Properties                                                              Cured State                                                                            No Cure                                                                            No Cure                                                                            No Cure                                                                            No Cure                                                                            Partial                                                                           No Cure                                      00 Durometer                                                                           --   --   --   --   --  --                                           Elongation at Break                                                                    --   --   --   --   --  --                                           __________________________________________________________________________

                  TABLE IV                                                        ______________________________________                                        Examples    3          4          5                                           ______________________________________                                        PPG-425     --         --         --                                          PPG-1000    50         --         --                                          PPG-2000    --         70         --                                          PTMEG-2000  --         --         50                                          Paraplex G-60                                                                             50         30         50                                          Sn/Ti Catalyst 1A                                                                         17         17         17                                          Polyol Properties:                                                            Type        Ether      Ether      Ether                                       Functionality                                                                             2          2          2                                           MW          1000       2000       1000                                        Gel Time @ RT                                                                             105 minutes                                                                              43 minutes 90 minutes                                  Cured Properties:                                                             Cured State Brittle    Brittle    Brittle                                     00 Durometer                                                                              59         53         80                                          Elongation at Break                                                                       <25%       <25%       <25%                                        ______________________________________                                    

EXAMPLES 6-9 AND COMPARATIVE EXAMPLES J-L

Following the procedure described in Example 2 and Comparative ExamplesA-C above, the compositions of Examples 6-9 and Comparative Examples J-Lwere prepared, cured and evaluated using the compounds listed below inTable V.

                  TABLE V                                                         ______________________________________                                        Hydroxy Functional                                                                          Polyethylenebutylene Adipate Glycol of                                        molecular weight 1000                                                         (PEBAG-1000)                                                                  Polybutadiene R45HT (as in Example 2)                                         Pentaerythritol monoricinolate                                                (Caschem, Inc)                                                  Epoxy Functional                                                                            Paraplex G-60 (as in Example 2)                                 Curative Catalyst                                                                           Sn/Ti Catalyst 1A                                               ______________________________________                                    

Tables VI and VII below describe gel time, summarize the properties ofthe multi-functional hydroxy compounds and display the cured propertiesof the compositions of Examples 2 and 6-9 and Comparative Examples J-L.

These examples show that the compositions of the present invention cancomprise a wide variety of multi-functional hydroxy compounds includinghydroxy-functional butadiene, polyether polyols, polyester polyols, andhydroxylated natural oils such as castor oil.

Multi-functional hydroxy compounds of molecular weight in excess of 500produce useful encapsulant compositions. Multi-functional hydroxycompounds having molecular weights ranging from about 1000 to about 4000are preferred.

The examples of Tables VI and VII also show that the amount ofmulti-functional epoxy compound needed to cure the multi-functionalhydroxy compound is dependent on the molecular weight of themulti-functional hydroxy compound.

The examples of Tables VI and VII demonstrate that a particularly usefulamount of the multi-functional epoxy compound can range from about 5-50%by weight, preferably, 10-50% by weight, and more preferably, 17-50% byweight, of the resultant mixture of the multi-functional expoxy compoundand the multi-functional hydroxy compound.

                  TABLE VI                                                        ______________________________________                                        Comparative Examples                                                                      J         K         L                                             ______________________________________                                        PEBAG-1000  83        --        --                                            Polybutadiene R45HT                                                                       --        95        --                                            Flexricin 17                                                                              --        --        50                                            Paraplex G-60                                                                             17        5         50                                            Sn/Ti Catalyst 1A                                                                         17        17        17                                            Polyol Properties                                                             Type        Ester     Polymeric Pentaerothitol                                                                Monoricinoleate                               Functionality                                                                             2         2.3       4                                             MW          1000      2800      416                                           Gel Time @ RT                                                                             >3 hr.    2-18 hr.  >2 hr.                                        Cured Properties                                                              Cured State No Cure   Thick Gel No Cure                                       00 Durometer                                                                              --        Poor      --                                            Elongation at Break                                                                       --        Cure      --                                            ______________________________________                                    

                  TABLE VII                                                       ______________________________________                                        Examples 2        6       7      8      9                                     ______________________________________                                        PEBAG-1000                                                                             --       50      --     --     --                                    Polybutadiene                                                                          83       --      90     50     --                                    R45HT                                                                         DB Oil   --       --      --     --     50                                    Paraplex G-60                                                                          17       50      10     50     50                                    Sn/Ti Catalyst                                                                         17       17      17     17     17                                    1A                                                                            Polyol                                                                        Properties                                                                    Type     Polymeric                                                                              Ester   Polymeric                                                                            Polymeric                                                                            Glyceryl                                                                      Tricin-                                                                       oleate                                Functionality                                                                          2.3      2.0     2.3    2.3    3                                     MW       2800     1000    2800   2800   942                                   Gel Time @                                                                             11 min.  15 min. 61 min.                                                                              2 min. 13 min.                               RT                                                                            Cured                                                                         Properties                                                                    Cured State                                                                            Flexible Limited Flexible                                                                             Brittle                                                                              Brittle                                                 Flexi-                                                                        bility                                                      00 Durometer                                                                           36       78      24     87     83                                    Elongation at                                                                          50-75%   25%     100%   <25%   <25%                                  Break                                                                         ______________________________________                                    

EXAMPLES 10-15 AND COMPARATIVE EXAMPLES M AND N

Following the procedure described in Example 2 and Comparative ExamplesA-C above, the compositions of Examples 10-15 and Comparative Examples Mand N were prepared, cured and evaluated using the multi-functionalhydroxy compound, multi-functional epoxy compounds, and curativecatalyst, listed below in Table VIII below.

                  TABLE VIII                                                      ______________________________________                                        Hydroxy Functional                                                                       Polybutadiene R45HT, a hydroxy-functionalized                                 polybutadiene liquid elastomer (as in Example 2)                   Epoxy Functional                                                                         Paraplex G-60, epoxidized soybean oil (as in                                  Example 2)                                                                    Flexol LOE, epoxidized linseed oil (Union Carbide)                            Monoplex S-73, epoxidized octyl tallate (CP Hall)                             Epirez 510, diglycidal ether of bisphenol A (Shell                            Chemical Company)                                                             Epirez 50727, a proprietary highly-reactive                                   diglycidyl ether (Shell Chemical Co.)                                         Heloxy 5048, trimethylol propane triglycidylether                             (Shell Chemical Co.)                                                          Poly BD 600 and 605, olefinic epoxidized                                      polybutadiene with 3.5% and 6.5% oxiraneoxygen,                               respectively (Elf Atochem N.A.)                                    Curative Catalyst                                                                        Sn/Ti Catalyst 1A                                                  ______________________________________                                    

Tables IX and X below describe gel time, summarize epoxy properties anddisplay the cured properties of the compositions of Examples 10-15 andComparative Examples M and N.

                  TABLE IX                                                        ______________________________________                                        Examples  M       N       2      10     11                                    ______________________________________                                        Poly BD R45HT                                                                           83      50      83     83     83                                    Paraplex G-60                                                                           --      --      17     --     --                                    Flexol LOE                                                                              --      --      --     --     --                                    Monoplex S-73                                                                           17      50      --     --     --                                    Epirez 510                                                                              --      --      --     17     --                                    Epirez 50727                                                                            --      --      --     --     17                                    Heloxy 5048                                                                             --      --      --     --     --                                    Poly BD 600                                                                             --      --      --     --     --                                    Poly BD 605                                                                             --      --      --     --     --                                    Sn/Ti Catalyst 1A                                                                       17      17      17     17     17                                    Epoxy Properties                                                              Type      Olefinic                                                                              Olefinic                                                                              Olefinic                                                                             Aromatic                                                                             Aromatic                                                               Glycidyl                                                                             Glycidyl                              Functionality                                                                           1.3     1.3     4.4    2      2                                     MW        420     420     1000   376    620                                   Gel Time @ RT                                                                           >4 hr.  >4 days 11 min.                                                                              "66 min.                                                                             "64 min.                              Cured Properties                                                              Cured State                                                                             No      No      Flexible                                                                             Flexible                                                                             Flexible                                        Cure    Cure                                                        00 Durometer                                                                            --      --      36     47     15                                    Elongation at                                                                           --      --      50-75% 125%   >200%                                 Break                                                                         ______________________________________                                    

                  TABLE X                                                         ______________________________________                                        Examples  12           13       14     15                                     ______________________________________                                        Poly BD R45HT                                                                           83           83       83     83                                     Paraplex G-60                                                                           --           --       --     --                                     Flexol LOE                                                                              --           --       --     17                                     Monoplex S-73                                                                           --           --       --     --                                     Epirez 510                                                                              --           --       --     --                                     Epirez 50727                                                                            --           --       --     --                                     Heloxy 5048                                                                             17           --       --     --                                     Poly BD 600                                                                             --           17       --     --                                     Poly BD 605                                                                             --           --       17     --                                     Sn/Ti Catalyst 1A                                                                       17           17       17     17                                     Epoxy Properties                                                              Type      Aliphatic Glycidyl                                                                         Olefinic Olefinic                                                                             Olefinic                                         Ether                                                               Functionality                                                                           3            2.8      5      5.9                                    MW        465          1300     1300   1000                                   Gel Time @ RT                                                                           "47 min.     "44 min. <1 min.                                                                              9 min.                                 Cured Properties                                                              Cured State                                                                             Flexible     Flexible Flexible                                                                             Flexible                               00 Durometer                                                                            69           12       17     57                                     Elongation at                                                                           50%          175%     N/T    50-75%                                 Break                                                                         ______________________________________                                    

These examples demonstrate that an epoxy-functional compound useful inthe composition of this invention has two (2) or more epoxy groups perchain.

These examples also demonstrate the use of a wide variety ofepoxy-functional compounds in the composition of this invention,including, e.g., epoxidized olefinically unsaturated natural oils,aromatic glycidyl ethers, aliphatic glycidyl ethers, epoxidizedolefinically unsaturated polymers, and glycidyl ether functionalpolymers.

EXAMPLES 16 AND 17

Following the procedure described in Example 2 and Comparative ExamplesA-C above, the compositions of Examples 16 and 17 were prepared, curedand evaluated using the hydroxy-functional compound, epoxy-functionalcompounds, and curative catalysts listed below in Table XI.

                  TABLE XI                                                        ______________________________________                                        Hydroxy-Functional                                                                       Polybutadiene R45HT, a hydroxy functionalized                                 polybutadiene liquid elastomer (as in Example 2)                   Epoxy-Functional                                                                         Paraplex G-60, epoxidized soybean oil (as in                                  Example 2)                                                         Curative Catalyst                                                                        BF.sub.3.Etherate (boron trifluoride complex with diethyl                     ether) (BASF)                                                      Curative Catalyst                                                                        Ancamine 1170 (proprietary boron trifluoride-amine                            complex, designed for elevated-temperature cures)                             (Pacific Anchor Chemical Company)                                  ______________________________________                                    

Table XII below describes gel time and displays the cured properties ofthe compositions of Examples 16 and 17.

                  TABLE XII                                                       ______________________________________                                        Examples        16        17                                                  ______________________________________                                        Poly BD R45HT   83        83                                                  Paraplex G-60   17        17                                                  BF.sub.3.Etherate                                                                             1.8       --                                                  Ancamine 1170   --        17                                                  Gel Time @ RT   <1 min.   --                                                  (Stick Test)                                                                  Gel Time @ 100° C.                                                                     --        <30 min.                                            (Stick Test)                                                                  Cure Conditions 800 min./RT                                                                             60 min./100° C.                              Cured State     Flexible  Flexible                                            00 Durometer    69        0                                                   Elongation at   50-100%   >200%                                               Break                                                                         ______________________________________                                    

These examples demonstrate the use of other types of Lewis acidcatalysts such as boron trifluoride complexes in the composition of thisinvention.

EXAMPLES 18-20

Following the procedure described in Example 2 and Comparative ExamplesA-C above, the compositions of Examples 18-20 were prepared, cured andevaluated using the multi-functional hydroxy compound, multi-functionalepoxy compounds, curative catalyst, and diluents, listed below in TableXIII below.

                  TABLE XIII                                                      ______________________________________                                        Hydroxy Functional                                                                       Polybutadiene R45HT, a hydroxy functionalized                                 polybutadiene liquid elastomer (as in Example 2)                   Epoxy Functional                                                                         Paraplex G-60, epoxidized soybean oil                                         (as in Example 2)                                                  Curative Catalyst                                                                        Sn/Ti Catalyst 1B                                                  Diluent    Monoplex S-73, epoxidized octyl tallate                                       (from CP Hall)                                                     Diluent    Plasthall 100, octyl tallate (from CP Hall)                        Diluent    100 Solvent Neutral Oil, high purity petroleum oil                            (from Exxon)                                                       ______________________________________                                    

Table XIV below describes gel time and displays the cured properties ofthe compositions of Examples 18-20.

                  TABLE XIV                                                       ______________________________________                                        Examples   18      19           20                                            ______________________________________                                        Poly Bd R45HT                                                                            59      59           59                                            Paraplex G-60                                                                            41      41           41                                            Monoplex S-73                                                                            70      --           --                                            Plasthall-100                                                                            4       74           4                                             100 Solvent Neutral                                                                      --      --           70                                            Oil                                                                           Sn/Ti Catalyst 1B                                                                        27      27           27                                            Gel Time,  55 min. 22 min.      10 min.                                       Stick Test                                                                    Cured Properties                                                              Cured State                                                                              Flexible                                                                              Limited Flexibility                                                                        Limited Flexibility                           00 Durometer                                                                             25      55           59                                            Elongation at                                                                            50%     25%          25%                                           Break                                                                         ______________________________________                                    

These examples demonstrate the use of diluents in the composition of thepresent invention. Such diluents can include, e.g., epoxy-functionalizedor non-functionalized materials.

Examples of useful functionalized materials include epoxidized olefinicnatural oils having less than two epoxy groups per chain, monoglycidylethers on short-chain alcohols, monoglycidyl ethers on long-chainalcohols, and the like.

Examples of useful non-functionalized materials include petroleumethers, synthetic hydrocarbon oils, ester diluents, and the like.

EXAMPLE 18 AND COMPARATIVE EXAMPLES O-Q

Following the procedure described in Example 2 and Comparative ExamplesA-C above, the compositions of Examples 18 and Comparative Examples O-Qwere prepared, cured and evaluated as indicated in Table XV below.

Table XV also describes the properties of the compositions of Example 18and Comparative Examples O-Q.

                  TABLE XV                                                        ______________________________________                                        Examples     O        P        Q     18                                       ______________________________________                                        Type         Urethane Maleated Epoxy Hydroxy/                                                                      Epoxy                                    Polymer                                                                       Hydroxy Poly Butadiene.sup.1                                                               X        X        --    X                                        Maleate Poly Butadiene.sup.2                                                               --       X        --    --                                       Epoxy EP Polymer.sup.3                                                                     --       --       X     --                                       Curative Catalyst                                                             Isocyanate   X        --       --    --                                       Amine        --       X        --    --                                       Multi-functional Epoxy                                                                     --       --       --    X                                        Lewis Acid Catalyst.sup.3                                                                  --       --       X     X                                        Properties                                                                    Clarity      Clear    Clear    Opaque                                                                              Clear                                    Mixing Determined By:                                                                      Time     Time     Color Color                                    Re-Entry     Difficult                                                                              Difficult                                                                              Easy  Easy                                     Adhesion, lbs†                                                                      2-4      1.5      2.8   4.5                                      ______________________________________                                         †Adhesion to conductor wire coated with an extended thermoplastic      rubber cable filler grease. Force, in lbs., required to pull 114              millimeters (4.5 inches) in length of coated conductor out of encapsulant     at 60° C. after curing at room temperature.                            .sup.1 Average for typical urethanes such as Caschem 126 and 3M Gella         4441.                                                                         .sup.2 3M High Gel 4442.                                                      .sup.3 Trilene TE141 (Uniroyal Chemical Company).                        

Example 18 and Comparative Examples O-Q demonstrate the advantages ofthe present invention over other known commercially-availableencapsulant materials, including urethanes, such as Caschem 126 andGella 4441 (3M Company, Chemical Division, St. Paul, Minn.), andmaleated compositions such as High Gel 4442 (3M). Commercially availableepoxy encapsulant materials include Trilene TE-141 (Uniroyal Chemical).

Several properties, such as clarity, re-entry, and adhesion weremeasured and tabulated in Table XV.

Compared to a urethane composition of Comparative Example N, thecomposition of Example 18 was easier to mix, was easier to re-enter,adhered better to grease-coated wire, and contained no isocyanates.

Compared with the maleated polybutadiene formulation Comparative ExampleO, the composition of Example 18 was easier to mix, was easier tore-enter, and adhered better to grease-coated wire.

Compared with the epoxidized liquid ethylene/propylene composition ofComparative Example P, the composition of Example 18 possessed betterclarity and adhered better to grease-coated wire.

What is claimed is:
 1. A signal transmission device comprising anencapsulated segment wherein the encapsulated segment is produced by amethod which comprises contacting the segment of the signal transmissiondevice to be encapsulated with an effective amount to encapsulate thesegment, of a room-temperature curable composition comprising:(1) ahydroxy-functional compound having a molecular weight of greater than500 and a hydroxy functionality of 2 or more; (2) a 1,2-epoxy-functionalcompound having an epoxy functionality of 2 or more; and (3) a curativecatalyst, in an amount effective to crosslink the epoxy and hydroxycomponents of the respective epoxy-functional and hydroxy-functionalcompounds.
 2. A signal transmission device as recited in claim 1 whereinthe hydroxy-functional compound is selected from the group consisting ofhydroxy-terminated polybutadiene, hydroxy-terminatedpolybutadiene-styrene, hydroxy-terminated polybutadiene-acrylonitrile,hydroxy-functionalized ethylene-propylene copolymers or terpolymers,castor oils, hydroxy-functionalized polyisoprene, polyester polyols,polyether polyols, and combinations thereof.
 3. A signal transmissiondevice as recited in claim 1 wherein the epoxy-functional compound isselected from the group consisting of an epoxidized olefinicallyunsaturated natural oil, an aromatic glycidyl ether, an aliphaticglycidyl ether, an epoxidized olefinically unsaturated polymer, anglycidyl ether functional polymer, and combinations thereof.
 4. A signaltransmission device as recited in claim 3 wherein the epoxy-functionalcompound is selected from the group consisting of an epoxidized soybeanoil, an epoxidized linseed oil, a diglycidyl ether of bisphenol A, adiglycidyl ether of 1,4-butanediol, an epoxidized polybutadiene polymer,an epoxidized ethylene-propylene polymer, and combinations thereof.
 5. Asignal transmission device as recited in claim 1 wherein the curativecatalyst comprises a Lewis acid.
 6. A signal transmission device asrecited in claim 5 wherein the Lewis acid is selected from the groupconsisting of boron trifluoride, tin tetrachloride, aluminumtrichloride, aluminum tribromide, zinc chloride, silicon tetrachloride,and ferric chloride.
 7. A signal transmission device as recited in claim1 wherein the curative catalyst is a catalyst composition whichcomprises:(1) a catalytically effective amount of a Lewis acid; and (2)a titanate having the structure

    Ti(OR.sup.1)(OR.sup.2)(OR.sup.3)(OR.sup.4)

wherein R¹, R², R³ and R⁴ are each independently alkyl or aryl.
 8. Asignal transmission device as recited in claim 7 wherein the Lewis acidis selected from the group consisting of boron trifluoride, tintetrachloride, aluminum trichloride, aluminum tribromide, zinc chloride,silicon tetrachloride, and ferric chloride.
 9. A signal transmissiondevice as recited in claim 7 wherein the titanate is selected from thegroup consisting of tetraisopropyl titanate, tetra-n-butyl titanate,tetraisobutyl titanate, tetra-t-butyl titanate, tetra-2-ethylhexyltitanate, tetradodecylphenoxy titanate, tetranonylphenoxy titanate, anddiisopropyl dinonylphenoxy titanate.
 10. A signal transmission device asrecited in claim 1 wherein the encapsulated segment of the signaltransmission device is a splice, a pressure block, or an end block, in acopper cable or fiber optic cable.